This invention relates to a pitch controlling device of a marine propeller.
In the case of prior art, a servomotor for controlling the pitch of a propeller is provided generally in a hub of the propeller, or in a shafting as shown in FIG. 1 and FIG. 2. And, owing to the provision or a servomotor in hub or in shafting, they are obliged to use a stationary member embracing a rotating member to introduce pressure oil to the servomotor, and further, the oil passages in the hub and in shafting are relatively complex. Therefore, in these devices, a leakage of oil rises to a fairly large amount and it often causes an inaccurate operation. These kind of devices include also various parts which are arranged in spaces of low accessibility. Thus, in the case of prior art, a relatively long time and a fairly large amount of cost are necessary for the repairing of the parts.
Further, in the cases of above heretofore known devices, the shaft of the propeller must be provided with a long center bore and branch bores for the feeding of oil or for the provision of a force transmitting member. And, upon providing these bores, it is necessary to use special machine tools.